The reactor is used in various applications. The representative reactor includes a series reactor connected serially to an electric motor circuit to limit a current when a short circuit occurs, a parallel reactor to stabilize a current share among parallel circuits, a current-limiting reactor to limit a current when a short circuit occurs and to protect a machine connected thereto, a starting reactor connected serially to the electric motor circuit to limit a starting current, a shunt reactor connected in parallel to a transmission line to compensate for leading reactive power or to suppress an abnormal voltage, a neutral point reactor connected between the neutral point and the ground to limit a ground fault current flowing when a ground fault accident of an electric power system occurs, and an arc-extinguishing reactor to automatically extinguish electric arc appearing when one-line ground fault of a three phase electric power system occurs, or a like.
It is requested that electrical specifications of electrical parts such as a transformer, choke coil, or a like including a reactor be satisfied in relation to electrical circuits or a like to be used. In particular, when a reactor is used as a boosting reactor or a like in a high current circuit, it is important that specifications related to DC superimposition characteristics of a high current value are satisfied.
FIG. 1 is a perspective view showing a core of a conventional reactor part. The conventional core 9 is made up of, for example, sheet members 6 to be inserted as a member for a magnetic gap among each of several magnetic substance blocks 3a and several magnetic substance blocks 3b. The core 9 is of an approximately ring-like shape as a whole and has two straight line portions made up of the magnetic substance blocks 3b in which a winding (not shown) is wound around each straight line portion with a winding frame portion of a bobbin (not shown) interposed between each winding and the straight line portions to obtain specified electric characteristics. Each of the blocks 3a made of a magnetic substance is coupled to each of the straight line portions of the blocks so that the core 9 has the approximately ring-like shape.
Incidentally, the conventional core 9 has a core shape having a cross-sectional core area being uniform relative to a magnetic path (for example, Patent Reference 1). That is, the core 9 shown in FIG. 1 is so configured that the height Ha of the block 3a made of the magnetic substance is equal to the height Hb of the block 3b made of the magnetic substance and that the width Wa of the block 3a made of the magnetic substance is equal to the width Wb of the block 3b made of the magnetic substance. Therefore, the core 9 is constructed so that a cross-sectional area in a direction orthogonal to a magnetic path of the magnetic substance block 3b making up the winding portion around which the winding is wound is equal to the cross-sectional area in the direction orthogonal to the magnetic path of the magnetic substance block 3a making up a non-winding portion around which no winding is wound.
Patent Reference 1: Japanese Patent Application Laid-open No. 2003-124039